Location

src/contrib/SignalProcessing/VisualizationDemo

Synopsis

The VisualizationDemo signal processing module demonstrates how to send visualizations with arbitrary pixel content to the operator module. Two rendering methods are provided: Native Qt QPainter-based rendering, and BCI2000's own GraphDisplay based rendering.

Inheritance

Function

The VisualizationDemoFilter computes the determination coefficient (squared correlation, values) between its first and second input channel. The determination coefficient is visualized in form of a pie chart, and the pie chart is sent to the operator module as bitmap visualization data.

For various values of the value, the operator visualization window appears as follows:

Display of a small value

Display of a medium value

Display of a large value

Implementation

A BitmapVisualization object is used to send visualization window configuration, and bitmap data to the operator module. In the filter's Initialize() method, the bitmap visualization object's SendReferenceFrame() method is called to set an anchor for further visualization data. In the filter's Process() method, rendered visualization data is sent to the operator module using the bitmap visualization object's SendDifferenceFrame method as an update to existing image data.